1. Field of the Invention
This invention is directed to a heating device, and in particular to a self-contained multi-purpose, hand portable heating device that can be used as a cooling stove, as an oven, or as a spaceheater.
2. Description of the Prior Art
There is a long history of efforts that have been made in the past to provide portable cooking apparatus.
Included in this are the following United States patents:
Dahman: U.S. Pat. No. 758,899 May 1904, which shows a knock-down oven having hollow walls for purposes of insulation, held by removable snap fasteners; there appears to be no provision for air circulation through the hollow walls; PA0 McBride: U.S. Pat. No. 1,461,280July 1923, which shows a removable oven having hollow walls, for use over a stove burner, without any provision being made for secondary air, necessary for obtaining an effective thermal gradient between internal and external oven surfaces, for safety purposes; PA0 Dukes: U.S. Pat. No. 2,057,373 Oct. 1936, which shows a portable oven having an alcohol burner as its heat supply; PA0 Horsman: U.S. Pat. No. 2,072,036 Feb. 1937, which shows a portable, cannister-like bake-oven for use with a gas or electric stove; PA0 Stanely: U.S. Pat. No. 2,077,777 Apr. 1937, which shows a hollow wall oven for use upon an oil, gas or electric stove; PA0 Bartlebaugh: U.S. Pat. No. 2,189,875 Feb. 1940, which shows a portable, hollow walled oven having a complex circulatory air flow; PA0 Fader: U.S. Pat. No. 2,501,935 Mar. 1950, which shows a portable sheet metal oven for use over an external gas or oil burner; PA0 Little et al: U.S. Pat. No. 3,308,807 Mar. 1967, which shows the well known Coleman foldable oven for use over a camp stove; PA0 Balls: U.S. Pat. No. 3,354,878 Nov. 1967, which shows a portable range incorporating a firebox and a variable thickness oven bottom; PA0 Dahlquist: U.S. Pat. No. 3,867,922 Feb. 1975, which shows a dissassembleable portable oven, secured by threaded rods and wing-nuts; PA0 Norman: U.S. Pat. No. 4,051,837 Oct. 1977, which shows an outer and a separate inner casing for use upon a camp stove; PA0 Noh: U.S. Pat. No. 5,101,805 Apr. 1992, which shows a gas cooker having a mechanism permitting use as an oven or as a grill.
In considering and comparing portable type ranges and ovens with orthodox kitchen appliances, it should be born in mind that whereas the regular appliances include internal insulation, so as to lower the sides and back temperatures sufficiently to enable the appliance to be sandwiched safely against adjoining cupboards, the portable type of device is not so protected, mainly on the bases of weight, cost and size, and thereby, in the foregoing prior art embodiments, these operate at thigh surface temperatures, and require significant peripheral safety clearances to reduce the danger of fire or injury.
While many of the appearance characteristics of the present invention can be seen in the foregoing prior art, there is no prior teaching to lead one to provide the safety characteristics, particularly a relatively cool outer casing, that give the present invention its unexpected characteristics and capabilities.